The redox thermodynamics and kinetics of flavonoid rutin adsorbed at glassy carbon electrodes by stripping square wave voltammetry

FRANCISCO EDUARDO ARAGÃO CATUNDA JR; MARCELO FRANCISCO DE ARAUJO; ADRIAN MARCELO GRANERO; FERNANDO JAVIER ARÉVALO; MARIO GERALDO DE CARVALHO; MARÍA ALICIA ZÓN; HÉCTOR FERNÁNDEZ

ELECTROCHIMICA ACTA

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2011 p. 9707 - 9713

0013-4686

The adsorptive accumulation of rutin (RU) at glassy carbon (GC) electrodes in 10% ethanol + 90%1 mol dm−3 HClO4 aqueous solution is studied by using cyclic (CV) and square wave (SWV) voltammetries.The Frumkin adsorption isotherm best described the specific interaction of rutin with carbon electrodes.By fitting the experimental data, values of −31.9 kJ mol−1 and 0.54 ± 0.02 were obtained for the Gibbs freeenergy of adsorption and the interaction parameter, respectively. SWV fully characterized the thermodynamicsand kinetics of the surface redox process, using a combination of the “quasi-reversible maximum”and the “splitting of SW peaks” methods. Average values of 0.644 ± 0.003 V and 0.44 ± 0.02 were obtainedfor the formal potential and the anodic transfer coefficient, respectively. Moreover, a formal rate constantof 6.1 × 102 s−1 was obtained. SWV was also employed to generate calibration curves. The lowestconcentration of RU experimentally measured for a signal-to-noise ratio of 3:1 was 2 × 10−8 mol dm−3(12 ppb).